In my case where n=2, naps during the day are/were not all that consistent but at night (unless they are very sick or something) the kids sleep.
Can’t say many other things worked equally well for all three kids, but that did.
This is one of the very-rare things that actually worked for all of them, almost exactly the same, all three times.
I'd say the only other things we did that worked 3-for-3 were making the kids walk on their own early and often, as much as feasible, and never having snacks (nor, very relatedly, tablets/phones) for them on-hand when out e.g. running errands—we just never introduced that as even a possibility. We didn't end up with kids still stroller/carrier-dependent past age ~2, and our kids have never had a meltdown[0] or complained about a lack of snacks (or digital toys) when we were out running errands. We reaped benefits by not needing to cart strollers and carriers around nearly as much, and never having to worry about snack-logistics or related mess (God knows we have plenty of other messes to worry about). IDK whether or how much those approaches benefited our kids, but they sure benefitted us.
[0, editing this in] To be clear, each went through period where they'd occasionally have public melt-downs, but never because we ran out of snacks or had the wrong snack or whatever, or because we wouldn't give them our phones to play with. I suspect short-circuiting these exact sorts of meltdowns is how the snacks-in-stores and sitting-in-the-cart-with-a-phone situations come to be (aside from some parents seeming to just think young kids need food available constantly or they might starve? These people baffle me, but do seem to actually exist) but our general rule we followed whenever possible was not to lean on a crutch that we didn't want to end up needing forever. That principle served us well, I think. Tens of embarrassing minutes we might have avoided, but that saved us a ton more hassle later.
Again, n=2 for me personally but as I mentioned in my reply to another comment we also had a friend with a "baby who won't sleep" and when they tried it also worked for them.
I don't make a habit of recommending this to people unless I'm close with them, bc I know that some people may take it personally or believe they are an exception. And I'd bet money that there are plenty of exceptions. But I also think they're exceptions rather than the rule. Whenever I've seen parents who believe that their baby can sleep through the night and work towards that goal, they seem to get there pretty quickly.
Edit to add: To put it in engineering terms, I think part of the problem is that you have to escape a local maximum of baby sleep. You may suffer several nights (possibly a couple weeks) that are worse than what you're used to in order to get to a place that's significantly better than what you're used to. When you're already sleep deprived, that can feel like a big hump to get over.
I'm emphasizing it bc many people are surprised by this, but if you know it's possible, you can start to work towards it. My partner's coworker has a ~1 year old who was still waking up (maybe multiple times?) each night to eat. She introduced them to one of those books (the 12-by-12 one) and they were very grateful.
Thanks for your recommendation anyway. I'm sure that there are many science-based techniques to "tame" children and make child care as atomic family bearable.
We didn't force anything or ignore him. And you don't have to believe me, but I'd encourage you to research more for yourself if waking up at night to feed a baby is something you're currently dealing with.